Hand Soap Could Cause Liver Cancer, New Study Says

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A common antimicrobial agent called triclosan causes liver fibrosis and cancer in laboratory mice through mechanisms also relevant to humans, researchers at the University of California, San Diego School of Medicine have found

Triclosan's broad use in consumer goods -- including liquid hand soaps, toothpastes, shampoos, cosmetics, plastics, yoga mats, cutting boards and ice cream scoops -- presents "a very real risk of liver toxicity for people, as it does in mice," said Robert H. Tukey, a UC-San Diego professor and co-author of the study, published Monday in Proceedings of the National Academy of Sciences.

Triclosan, a synthetic, broad-spectrum antibacterial chemical, is coming under fire because of its links to endocrine disruption that could cause infertility, impaired muscle function and now increased cancer risks.

It's All Around

The UC-San Diego study showed that mice exposed to triclosan for six months (roughly equivalent to 18 human years) had more and larger chemical-induced liver tumors than mice not exposed to the antimicrobial. Researchers believe triclosan may interfere with the protein responsible for detoxifying foreign chemicals in the body, thereby causing liver cells to proliferate and, over time, become cancerous tumors.

Studies have found traces of triclosan in 97 percent of breast milk samples from lactating women and in the urine of nearly 75 percent of people tested, according to a statement by UC San Diego Health System. Triclosan is also one of the seven most frequently detected compounds in streams across the United States, the statement says.

"We could reduce most human and environmental exposures by eliminating uses of triclosan that are high-volume, but of low-benefit, such as inclusion in liquid hand soaps," said Bruce D. Hammock, professor at University of California, Davis. "Yet we could also for now retain uses shown to have health value -- as in toothpaste, where the amount used is small."

Colgate-Palmolive (CL) recently came under fire because its Total toothpaste contains triclosan. A recent Care2 petition, asking Colgate to remove triclosan from its toothpaste, so far has received almost 68,000 signatures.

Triclosan is already under scrutiny by the U.S. Food and Drug Administration. On its website, the FDA says, "Triclosan is not currently known to be hazardous to humans. But several scientific studies have come out since the last time FDA reviewed this ingredient that merit further review."